Abstract?AIM: To determine the relation between each of the optical coherence tomography ( OCT) patterns, etiologies and visual acuity in patients with cystoid macular edema ( CME) .?METHODS:Fifty-seven eyes with CME from 52 patients were included in our study. The data of this cross sectional study was collected rfom p atient s wtih CME assessed by OCT, who also underwent fun dus photography and visual acuity test the same day. The best corrected visual acuity ( BCVA ) was assessed by using E chart a nd converted in logarithm of the minimum angle of resolution( logMAR ) . Thevisual acuity varied from 2.3 logMAR to 0 logMAR w ith a mean of 1.11±0.57. The etiology was determined from medical history and the fundus ph otograph of the patient. Four O CT grades established according to ratio between the vertical size of largest cyst and the maximum macular thickness (<30 %,≥30% <60%,≥60% <90%and≥90%) were considered. The correlation was established by calculating the Pearson's correlatio n coefficient “r” and the statistical significance was considered when P value was inferior to 0.05.?RESULTS: OCT grade I V was the most associated with very severe visual loss with the greatest mean VA of 1.96± 0.23 logMAR and the correlation between OCT grades and visual acuity was strongly statistically significant ( r =0.729, P <0.001 ). The central retinal vein occlusion ( CRVO) was the most underlying disease associated with worsev ision, with the gre atest mean VA of 2 logMAR and the correlation was statistically significant ( r=0.375, P=0.004).Another associated OCT pattern, the disruption of bot h inner segment/outer segment ( IS/OS) and external limiting membrane ( ELM) , was inversely associated with severe visual loss ( high mean VA=1.11 ±0.57 logMAR, with statistically significant correlation, r=-0.346, P=0.008 ) . The presence of both vitreoretinal traction components and outer retinal layers disruption were significantly associated with OCT grade IV ( r=0.390, P=0.003) and CRVO (r=0.362, P=0.006).?CONCLUSION:In this study, the OCT fourth grade and CRVO seem to be more significantly associated with the worse vision in patients with CME.